Rotary gear device to provide pulsating flow

ABSTRACT

This invention utilizes the rotary motion of a pair of gears to provide pulsating or reciprocating motion to a fluid. The device comprises a gear block containing a gear cavity, a power gear rotatably mounted in the gear cavity and operably connected to a power unit, a mutilated idler gear disposed in the cavity in meshing contact with the power gear, a fluid reservoir fluidly connected to the cavity, and a discharge conduit fluidly connected to the cavity, wherein during a complete revolution of the mutilated gear the fluid is pumped from the reservoir to the discharge conduit in a pulsating flow.

o I 1 {in l1 1 11 Uite es att 11 1 1111 3,869,224 Brinltman Mar. 4, 1975 [54] ROTARY GEAR DEVMZE TO PRoViDE 3,072,064 1/1963 Burkholder 418/191 PULSATHNG FLOW 3,192,860 7/1965 Hardison 1 417/315 3,466,019 5/1969 Bullough 418/191 [76] Inventor: Glen E. Brinkman, Oxford, Nebr.

[22] Filed: Dec. 26, 1972 [21] Appl. No.: 318,601

[52] U.S. Cl 417/383,'417/395, 418/191, 418/196, 60/477 [51] Int. Cl F041) 35/02, F04b 43/06, FOlc 1/08 [58] Field of Search 418/32, 191, 196, 205; 417/315, 383, 389, 395; 60/371, 477

[56] References Cited UNITED STATES PATENTS 2,391,973 1/1946 Hunter 418/107 2,511,660 6/1950 Wilson 1 1 418/196 2669840 2/1954 Joy 1 60/371 2,697,911 12/1954 Joy 1. 418/191 2,753,804 7/1956 Goss 417/395 2,990,783 7/1961 Oliver 418/102 Primary Examiner.lohn J. Vrablik Attorney, Agent, or Firml-lenderson & Strom [5 7] ABSTRACT This invention utilizes the rotary motion of a pair of gears to provide pulsating or reciprocating motion to a fluid. The device comprises a gear block containing a gear cavity, a power gear rotatably mounted in the gear cavity and operably connected to a power unit, a mutilated idler gear disposed in the cavity in meshing contact with the power gear, a fluid reservoir fluidly connected to the cavity, and a discharge conduit fluidly connected to the cavity, wherein during a complete revolution of the mutilated gear the fluid is pumped from the reservoir to the discharge conduit in a pulsating flow.

7 Claims, 12 Drawing Figures PATENTEU 41975 SHEET 2 BF 5 PATENTEDHAR 41915 3869224 SHEET U 0F 5 PATENTEUHAR 197s SHEET 5 OF 5 F IE. I/

FIG. 12

ROTARY GEAR DEVICE TO PROVIDE PULSATING FLOW BACKGROUND OF THE INVENTION Gas and liquid that is adverse to being pumped, i.e., low viscosity, low lubricating value, highly corrosive, abrasive, or that are injurious to people if leakage occurs, have created unique problems for manufacturers of pumps, particularly when high continuous pressure is required.

Reciprocating pumps and rotary pumps are two types of positive displacement pumps used for high pressure. Reciprocating pumps, use an eccentric or wobble plate to reciprocate the piston or plunger which moves the fluid being pumped in an accelerated or decelerated motion, thus producing pressure and flow variations. Reciprocating pumps are noted for their high efficiency throughout a wide range of pressures and volumes, however to minimize the inherent pressure and flow variations, a plurality of pistons or plungers can be used but then the high efficiency is offset by a high initial cost.

A gear pump is one type of rotary pump which is noted for simplicity, compactness, light weight, high operating speed, low initial cost, continuous pressure and flow, and is most efficient for pumping fluids having high viscosity and high lubricating value wich minimizes wear and internal leakage. They require close clearance for high volumetric efficiency, however the worn flat surfaces can be repaired by simple surface grinding. Gear pumps are self actuating and require no pilot gears. The simplest form utilizes only two spur gears which mesh together and rotate within a close fitting cavity, however spur gears may reduce efficiency because they can create excessive pressure by trapping fluid between the meshed teeth. This trapping can be minimized by placing pockets on each side of the gear where the teeth mesh together, or by utilizing special forms of teeth.

Reciprocating pumps and rotary pumps are not satisfactory for directly pumping adverse liquids and gases. However a reciprocating pump can be used with a diaphragm to indirectly pump adverse fluids. A reciprocating piston is used to oscillate a diaphragm by placing a hydraulic fluid between the piston and the diaphragm. The fluid serves as a lubricant and the hydraulic medium through which the mechanical force is transmitted to the diaphragm and thereby to the subsequent fluid being pumped. The hydraulic fluid leaks between the piston and its cylinder, therefore a valve arrangement is necessary to automatically reload the leakage back between the piston and the diaphragm. In order for a reloading valve to be opened, a screen is necessary to limit the movement of the diaphragm. The

adjustment of a reloading valve is difficult to maintain, therefore the diaphragm rides the limiting screen harshly and causes excessive wear of the diaphragm.

When a diaphragm pump is operated at too high a speed, the piston will cavitate the hydraulic fluid and create vapor between the piston and the diaphragm which fouls the efficiency of the pump. Unless provision is made to expel the vapor, the vapor accumulates and compresses without moving the diaphragm, therey destroying the efficiency of the pump.

This invention provides a gear device which will eliminate or minimize the foresaid problems and incorporates the majority of the advantages of both the reciprocating pump and the gear pump and is readily adapted to a diaphragm type pump.

SUMMARY OF THE INVENTION 5 This invention relates generally to a gear device for providing a reciprocating or pulsating flow of fluid to operate devices which in turn transmit a mechanical force.

The gear device includes a gear block having a gear cavity, a power gear rotatably disposed in the gear cavity and operably connected to a power unit, at least one mutilated idler gear rotatably disposed in the gear cavity in meshing contact with the power gear, a fluid reservoir fluidly connected to the gear cavity, and a conduit fluidly connected to the gear cavity.

In one use of the gear device the free end of the conduit can be fluidly connected to an auxiliary device such as a diaphragm pump or a spring biased piston, wherein the gear device during a portion of one rotation of the mutilated gear pumps hydraulic fluid from the reservoir to the auxiliary device and during another portion of the one rotation the auxiliary device will cause the hydraulic fluid to return to the reservoir through either a separate fluid passage or back through the gear cavity, as described hereinafter.

A gear device utilizing a pair of diametrically disposed mutilated gears with a power gear disposed therebetween can be fluidly connected to a piston wherein the flow from one of the: mutilated gears and the power gear will operate to move the piston in one direction and the flow from the other mutilated gear and the power gear will operate to move the piston in the opposite direction, thus by alternating the flow from the gears reciprocating motion can be provided to the piston.

The reservoir, the gears in their cavity, the resilient device and the interconnecting valveless passageways are related and designed to permit trapped air or vapor to be carried or buoyed to the reservoir. Furthermore, no reloading valves are required, no additional filling or bleeding ports are necessary and no diaphragm limiting device is required thereby eliminating unnecessary wear of the diaphragm.

The efficiency and properties of this invention can be altered considerably by changing the clearance between the gears and their casing, by utilizing devices having different resiliency, by changing the size and style of the gear teeth, by varying the diameter and thickness of the gears, by changing the number and portion of teeth that are mutilated, by varying the center distance between gears, by utilizing high viscosity hydraulic fluid, and/or by altering the relationship of the number of teeth on the power gear and the idler gear thereby changing the torque: necessary to drive the device for a given load and speed. Furthermore, each non-mutilated gear tooth, which meshes with other teeth acts as an independent plunger to displace a small quantity of hydraulic fluid thus providing steady flow, steady pressure and steady torque during the power portion of each revolution of the mutilated gear. When two mutilated gears and two resilient devices are used, a substantially continuous torque, flow and pressure are developed which eliminates the need for a flywheel, accumulator or an alleviator thus reducing the comparable weight and volume.

No dynamic seal is necessary for the leak proof operation of the gear device; however for other reasons a seal is provided around the vertical drive shaft of the power gear which projects upwardly from the reservoir.

The pulsating fluid force of the gear device can be utilized for thrusting a spring loaded piston, thus providing a reciprocating ram, or it can be used to oscillate a resilient diaphragm which in turn can pump other fluids; and it can be used for oscillating other resilient de- V1CS.

It is therefore an object of this invention to provide a gear device which provides reciprocating or pulsating motion to a fluid or to convert rotary motion into a pulsating motion of a fluid within a closed hydraulic circuit.

A further object of the invention is to provide a gear device wherein no valving is required in the fluid lines thereof.

Still another object of this invention is to provide a pulsating fluid motion wherein cavitation of the fluid does not substantially effect the efficiency of the device.

Still another object of the invention is to provide a unit which is extremely effective under a high pressure and low volume operating condition.

Still another object of the invention is to provide a pumping unit which will have substantially steady torque, steady flow, and constant pressure, and can be operated within a wide temperature range and a wide speed range.

Yet another object of this invention is to provide a gear device which needs no dynamic seal for leak proof operation, is effective in operation, extremely rugged in use, simple to manufacture, highly efficient in use, compact and light weight.

These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.

In the drawings as hereinafter described, a preferred embodiment of the invention is illustrated, however various modifications can be made thereto without departing from the true spirit and scope of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the rotary gear device of this invention;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is an exploded view thereof;

FIG. 4 is a bottom plan view of the reservoir plate;

FIG. 5 is sectional view taken along the lines 5 5 in FIG. 4;

FIG. 6 is a sectional view taken along the lines 6 6 in FIG. 4;

FIG. 7 is a top plan view of the gear plate, wherein the bottom plan view is substantially a mirror image thereof;

FIG. 8 is a bottom plan view of the bearing plate;

FIG. 9 is a schematic view of the fluid flow during a portion of one revolution of the mutilated gear;

FIG. 10 is a schematic view of the fluid flow during another portion of the one rotation of the mutilated gear.

FIG. 11 is a schematic view of the fluid flow from a pair of mutilated gears acting on a diaphragm pump; and

FIG. 12 is a schematic view of the fluid flow from a pair of mutilated gears acting on a piston.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and particularly to FIGS. 1 and 3, the rotary gear device of this invention is indicated generally by the numeral 10. The gear device 10 comprises a top plate 11, a reservoir plate 12, a gear plate 13, a bearing plate 14 and a bottom plate 15. Each of the plates 11 15 is rectangular and of equal size in plan view. A plurality of spaced holes 17 are drilled through each of the plates, wherein the holes in the respective plates are in alignment to receive a threaded bolt 18. The plates abutting surfaces are precision machined to provide a seal thus preventing leakage from the various passages formed between the plates as described hereinafter. On assembly, the threaded shank end of each bolt 18 receives a nut 19 thus permitting the plates to be tightly secured together.

The top plate 11 (FIG. 3), in addition to the holes 17 drilled therethrough along its longitudinal edges has an opening 21 formed through the center thereof. Substantially midway between the top surface 22 and the bottom surface 23 of the plate the opening 21 is reamed thus providing an enlargement 24 thereof in which an annular seal 26 is mounted. A bottom plan view of the top plate is a mirror image of the top plan view thereof.

Disposed immediately below the top plate 11 is the reservoir plate 12 (FIGS. 3 6). Three longitudinally spaced holes 27, 28 and 29 are drilled through the plate from its top surface 31 to its bottom surface 32. An annular reservoir 33 is formed in the reservoir plate by countersinking a hole around the center hole 28 from the top surface 31. A pair of grooves 34 are cut in the plate between the holes and the reservoir 33 for purposes hereinafter described. Fluidly connected to the reservoir are a pair of diametrically spaced slots 36 and 37 which are parallelly disposed to the axis of the center hole 28 and which extend from the top surface 31 to the bottom surface 32 of the plate.

Abutting the bottom surface 32 of the reservoir plate 12 is the top surface 38 of the gear plate 13 (FIGS. 3 and 7). Three overlapping gear holes 41 43 are drilled through the plate 13 in axial alignment with the reservoir holes 27 29 respectively and form the gear cavity 44. Four slots 46 49 are cut through the plate 13 in fluid communication with the cavity 44. It will be noted that each slot is disposed at the juncture of a pair of adjacent gear holes 41 43. The gear slots 46 and 48 are in alignment with reservoir slots 36 and 37 respectively and provide fluid communication between the reservoir 33 and the cavity 44. Rotatably disposed in the center hole 42 is a power gear 51 (FIGS. 3 and 7) having a power shaft 52 projecting axially from both sides thereof. The periphery of the gear 51 has a plurality of teeth 53 cut therein in a conventional manner.

Rotatably mounted in each of the outer gear holes 41 and 43 is a mutilated idlergear 54 (FIGS. 3 and 7). As each of the mutilated gears 54 are identical only one will be described, however like elements of each will be identified by like numerals. The mutilated gear 54 has a shaft 56 projecting axially from both sides thereof and the periphery of the gear has teeth 57 cut therein. Approximately one half of the gear is mutilated by removing a portion thereof both laterally and circumferentially. Thus it will be noted that a portion of the teeth 57 have full meshing capabilities with the power gear teeth 53 while the other portion of the teeth 57 have only partial meshing capabilities. The upper portion of the shafts 56, 52 and 56 are journally disposed in the reservoir holes 27, 28 and 29 respectively.

The bearing'plate 14 is depicted in FIGS. 3 and 8. Three spaced holes 61 63 are drilled through the plate 14 in axial alignment with the reservoir plate holes 27 29 respectively and journally receive the lower portion of the shafts 56, 52 and 56 respectively. Diametrically spaced from the center hole 62 are a pair of slots 64 and 66. The first slot 64 is in alignment with the gear plate slot 49 and the second slot 66 is in alignment with the gear plate slot 47. A pair of diametrically opposed bleed holes 67 and 68 are also drilled through the plate 14 and a groove 69 and 71 is formed in the bottom surface 72 of the plate 14 between the holes 61 and the bleed holes 67 and 68 respectively. The grooves 69 and 71 and the reservoir plate groove 34 (FIG. 3) are provided to relieve any pressure build up between the ends of the shaft 52 and the bottom plate and the top plate 11, and to provide lubrication between the shafts and the surface walls of the holes. Although not shown, needle bearings or other forms of bearings could be disposed around the shafts, or the mutilated idler gears could be rotatably mounted on fixed shafts.

Mounted in juxtaposition with the bottom surface 72 of the bearing plate 14 is the top surface 73 (FIGS. 2 and 3) of the bottom plate 15. The bottom plate 15 has a pair of exhaust ports 74 and 76 drilled therethrough in alignment with the slots 64 and 66 respectively.

In summary the major elements of the rotary gear device 10 and the flow of fluid therethrough will be described hereinafter (FIGS. 3 and 9 12). The rotary gear device comprises a reservoir 33 fluidly connected by a pair of passages 81 and 82 (as depicted by the reservoir plate slots 36 and 37 and the gear plate slots 46 and 48) to the gear cavity 44. Rotatably disposed in the gear cavity 44 are the power gear 51 and a pair of mutilated idler gears 54. Fluidly connecting the gear cavity to the exhaust ports 74 and 76 are a pair of conduits 83 and 84' (as depicted by the bearing plate slots 64 and 66 and the gear plate slots 47 and 49). The power gear 51 is connected through its shaft 52 to a power unit (not shown) in a conventional manner wherein rotary motion is imparted to the gear.

Referring now to FIGS. 9 and 10 the gear device is shown attached to a diaphragm pump 86. The pump 86 comprises a fluid circuitry having an inlet passage 87, an outlet passage 88, an inlet valve 89, an outlet valve 91, a pump cavity 92, and a diaphragm 93. The diaphragm is disposed across the pump cavity and separates it into two sections, an upstream section 94 and a downstream section 96. The downstream section 96 provides a passage between the inlet valve 89 and the outlet valve 91. The pump 86 is fluidly connected to the gear device at the exhaust port 74 wherein fluid from the device flows into the upstream section 94 to act on the diaphragm 93.

For purposes of clarity, the clearance between the teeth of the gears as they mesh is magnififed. However it should be readily recognized, that for maximum efficiency, there should be minimal clearance between the meshing teeth and between the periphery of the teeth and the cavity wall.

In FIG. 9 the full teeth of both the power gear 51 and the mutilated gear 54 are in meshing contact and fluid from the reservoir 33 flows by gravity through the passage 81 into the area formed between adjacent teeth of each gear. As each gear rotates the fluid is carried around the periphery of the cavity to the conduit 83 where it is discharged into the upstream cavity 94 of the diaphragm pump. The fluid causes the diaphragm to expand thus causing the inlet valve 89 to close and the exhaust valve 91 to open wherein liquid in the downstream section 96 is expelled] into the outlet passage 88. When the mutilated teeth contact the power gear teeth, it will be noted that a passage exists between the two gears because a portion of the teeth and the gear body are non-existent. This passage allows the fluid in the cavity to flow back to the passage 81 and then around the gears or back to the reservoir if any back pressure is applied to the fluid in the discharge passage 83 as by the diaphragm returning to its normal position because of its resiliency (FIG. 10). At the same time the exhaust valve 91 closes and the inlet valve 89 opens thus allowing additional liquid from the inlet passage 87 to flow into the downstream section 96.

In FIGS. 11 and 12, two mutilated gears 54 are depicted wherein the mutilated teeth of the gears are dis posed to permit fluid to be pumped by one of the gears and the other gear is permitting the fluid to flow back to the reservoir. The action of the gear device 10 thus operates two diaphragm pumps 86 in FIG. 11 or a double acting piston 97 in FIG. 12. The double acting piston 97 is being moved to the right by the fluid from the upper two gears and the fluid in the cylinder behind the piston is being returned to the reservoir through the lower two gears.

Movement of the piston (FIG. 112), for example from left to right, can be accomplished in one smooth action or it can be accomplished in two or more steps. That is, a plurality of stop go movements is possible by removing or mutilating additional; teeth from the unmutilated portion of the gear.

Although the diameter of the three gears and the amount of mutilation of the two mutilated gears are shown in the drawings as substantially identical, it is not intended to so limit the invention, as the diameter or mutilation of any one of the gears is dependent on the volume and characteristics of flow for which the device is designed.

Furthermore, additional power gears and mutilated gears can be added either in series or in parallel to provide variations in flow characteristics.

The gear device has been depicted as having five plates however certain ones can be combined without departing from the scope of the invention. In addition the holes 17 in the reservoir plate can be tapped to permit the bolts 18 to be threadably secured thereto, and the nuts 19 can be replaced by shorter bolts to permit the top plate 11 to be removed without disturbing the remaining plates. This modification in structure facilitates the charging of reservoir, passages and cavity with fluid, and the bleed off of any air or gas which may be trapped during the charging. It has also been observed that, when the unit is charged, the power gear should be manually rotated to allow trapped air or gas to escape from the device.

I claim:

1. A rotary gear device to provide pulsating fluid flow, the device comprising:

a gear block having a gear cavity formed therein and a hole formed through one wall thereof which communicates with said cavity, said cavity having an inlet port and an outlet port;

a toothed power gear rotatably mounted in said cavity and having a shaft disposed in said hole and projecting axially from said power gear;

a first idler gear rotatably mounted in said cavity in meshing engagement with said power gear, wherein said gears are operable to pump fluid from said inlet port to said outlet port, said first idler gear having a plurality of adjacent mutilated teeth formed by removing a portion of said teeth and a portion of the gear hub adjacent thereto, thus maintaining said meshing engagement during a full revolution of said first idler gear and creating a passage between said gears during a portion of said revolution;

a fluid reservoir disposed in said gear block and fluidly connected to said inlet port;

a discharge conduit formed in said gear block and fluidly connected to said outlet port;

barrier means mounted in said discharge conduit,

said barrier means being sequentially moveable between a first position and a second position by displacement of fluid in said discharge conduit; and

a second idler gear rotatably mounted in said cavity and disposed opposite said first idler gear in meshing engagement with said power gear, said second idler gear having a plurality of mutilated teeth formed by removing a portion of said teeth and a portion of the gear hub adjacent thereto, thus maintaining said meshing engagement during a full revolution of said second idler and creating a passage between said power gear and said second idler gear during a portion of said revolution, said cavity having a second inlet port and a second outlet port, wherein said gears are operable to pump fluid from said second inlet port to said second outlet port, said second inlet port fluidly connected to said reservoir, a second discharge conduit formed in said gear block and fluidly connected to said second outlet port, and second barrier means being sequentially moveable between a first position and a second position by displacement of fluid in said second discharge conduit 2. A rotary gear device as defined in claim 1 wherein said gears are horizontally disposed and said reservoir is disposed above said inlet ports.

3. A rotary gear device as defined in claim 2 wherein said shaft hole fluidly communicates with said reservoir.

4. A rotary gear device as defined in claim 3 wherein said first discharge conduit and said second discharge conduit are interconnected and said first barrier means and said second barrier means forms a piston having a piston rod connected thereto and projecting outwardly of said discharge conduit.

5. A rotary gear device as defined in claim 3 wherein approximately one half of the teeth of both said idler gears are mutilated and said mutilated portions are disposed in opposed relation to each other.

6. A rotary gear device as defined in claim 3 wherein said first barrier means is a diaphragm and said second barrier means is a diaphragm.

7. A rotary gear device as defined in claim 6 wherein said first discharge conduit and said seconddischarge conduit are fluidly interconnected downstream of each of said diaphragms. 

1. A rotary gear device to provide pulsating fluid flow, the device comprising: a gear block having a gear cavity formed therein and a hole formed through one wall thereof which communicates with said cavity, said cavity having an inlet port and an outlet port; a toothed power gear rotatably mounted in said cavity and having a shaft disposed in said hole and projecting axially from said power gear; a first idler gear rotatably mounted in said cavity in meshing engagement with said power gear, wherein said gears are operable to pump fluid from said inlet port to said outlet port, said first idler gear having a plurality of adjacent mutilated teeth formed by removing a portion of said teeth and a portion of the gear hub adjacent thereto, thus maintaining said meshing engagement during a full revolution of said first idler gear and creating a passage between said gears during a portion of said revolution; a fluid reservoir disposed in said gear block and fluidly connected to said inlet port; a discharge conduit formed in said gear block and fluidly connected to said outlet port; barrier means mounted in said discharge conduit, said barrier means being sequentially moveable between a first position and a second position by displacement of fluid in said discharge conduit; and a second idler gear rotatably mounted in said cavity and disposed opposite said first idler gear in meshing engagement with said power gear, said second idler gear having a plurality of mutilated teeth formed by removing a portion of said teeth and a portion of the gear hub adjacent thereto, thus maintaining said meshing engagement during a full revolution of said second idler and creating a passage between said power gear and said second idler gear during a portion of said revolution, said cavity having a second inlet port and a second outlet port, wherein said gears are operable to pump fluid from said second inlet port to said second outlet port, said second inlet port fluidly connected to said reservoir, a second discharge conduit formed in said gear block and fluidly connected to said second outlet port, and second barrier means being sequentially moveable between a first position and a second position by displacement of fluid in said second discharge conduit.
 2. A rotary gear device as defined in claim 1 wherein said gears are horizontally disposed and said reservoir is disposed above said inlet ports.
 3. A rotary gear device as defined in claim 2 wherein said shaft hole fluidly communicates with said reservoir.
 4. A rotary gear device as defined in claim 3 wherein said first discharge conduit and said second discharge conduit are interconnected and said first barrier means and said second barrier means forms a piston having a piston rod connected thEreto and projecting outwardly of said discharge conduit.
 5. A rotary gear device as defined in claim 3 wherein approximately one half of the teeth of both said idler gears are mutilated and said mutilated portions are disposed in opposed relation to each other.
 6. A rotary gear device as defined in claim 3 wherein said first barrier means is a diaphragm and said second barrier means is a diaphragm.
 7. A rotary gear device as defined in claim 6 wherein said first discharge conduit and said second discharge conduit are fluidly interconnected downstream of each of said diaphragms. 